Modern refrigerators may be provided with an ice maker for producing pieces of ice, normally in the form of ice cubes. The ice maker may typically be arranged in a freezer cabinet or in the freezer compartment of a double compartment refrigerator cabinet. The ice maker normally comprises a mould or a tray forming a plurality of mould cavities for receiving water and forming ice cubes when the water is freezing in the respective cavities. The ice maker may be manually operated, in which case the user manually supplies water to the mould and manually releases the pieces of ice from the mould. The ice maker may alternatively be semi or fully automatic, such that the supply of water and/or the harvesting of pieces of ice is made automatically. Upon harvesting, the pieces of ice may be collected in a storage container inside the refrigerator. There may also be provided a dispensing means for dispensing pieces of ice through the refrigerator door, so that the ice is made available from the outside of the refrigerator.
A general problem at ice makers is that the pieces of ice adheres to the walls of the mould cavities upon freezing of the water. Harvesting and especially automatic harvesting is thereby made difficult. In the prior art, different ways of overcoming this problem in order to accomplish automatic harvesting has been suggested.
One previously known automatic ice maker comprises a rigid ice tray of a metallic material, forming an array of mould cavities and a water supply conduit for supplying water to the cavities. The ice maker further comprises heating means for heating the tray and a set of mechanically movable fingers which are arranged to be movable in a respective cavity. At harvesting, the tray is first heated such that the mould wall contacting surfaces of the pieces of ice are melted in order to release the pieces of ice from the walls. The fingers are thereafter operated to push the pieces of ice out of the respective cavities, over the upper edge of the tray, such that they fall down to a storage container arranged below the tray.
A problem at this known device is that the harvesting requires heating of the ice. Such heating is naturally disadvantageous in regard of the overall energy consumption of the ice making process. Further more, the heating adversely influences the cooling capacity of the refrigerator in which the ice maker is arranged. This problem is especially severe at absorption refrigerators where the total cooling capacity is limited. A further problem at this known device is that the pieces of ice, upon harvesting, are spread over a comparatively large area, which corresponds to the total length of the tray. This in turn makes the use of a correspondingly large collecting area of the storage container necessary.
Another previously known ice maker comprises a tray made of a somewhat flexible plastic material. The tray forms a matrix of e.g. two or three columns with approximately ten rows of mould cavities. The tray is arranged rotatable about a longitudinal axis, which is parallel to the cavity columns. A rotation stop is arranged at one corner of the tray, such that the tray may be freely rotated approximately 180° from a starting position, in which the mould cavities are facing upwards. A drive means for rotating the tray is connected to the short side being distal from said corner. Water is supplied to the cavities when the tray is in the starting position. When freezing of the water is competed the drive means is operated to rotate the tray until it is turned upside down and said corner contacts the stop. The drive means then continues to apply a rotational force onto the short side being distal from said corner. Hereby the tray is twisted such that a torsional deformation is created whereby the walls of each cavity also are deformed. The cavity wall deformation squeezes the pieces of ices such that they are released from the cavity walls and fall down into a storage container, which is arranged below the tray.
This known devices has the advantage of not requiring heating. However, certain problems still remain. Repeated operation may for instance cause fatigue fracture of the tray. The comparatively small deformation of the cavity walls, especially at the ends of the tray further makes release of pieces of ice from these cavities uncertain. Also at this known device, the pieces of ice released from the tray are spread over a comparatively large area, which area corresponds to the area of the tray and which requires a comparatively large collecting area of the storage container.
EP 1 441 188 A1 describes a further known ice maker. This ice maker comprises a number of metallic tray cells which are linked together to form a closed curve conveyor. The conveyor is arranged movable around a pair of pulleys. A cooling and heating apparatus in the form of a Peltier element is arranged between the pulleys. The Peltier element is arranged to cool tray cells positioned above it and to heat tray cells positioned below it. In use, water is supplied to tray cells facing upwards and positioned above the Peltier element. The Peltier element absorbs heat from these upper tray cells to thereby accelerate the production of ice. When the water in the upper tray cells is frozen the pulleys are rotated to thereby move the upper tray cells such that they are positioned below the Peltier element and facing downwards. In this position the Peltier element radiates heat to the now lower tray cells, whereby the pieces of ice in these cells begin to melt. Thereby these pieces of ice are released from the lower tray cells and fall down into a storage tray arranged below the conveyor. A problem with this ice maker is that it requires additional energy for supplying power to the Peltier element. The heating of the lower tray cells also adversely effects the cooling capacity of the entire refrigerator in which the ice maker is arranged. Also at this ice maker, the pieces of ice released from the lower tray cells are spread over a comparatively large area, which area corresponds to the projected area of the conveyor and which requires a comparatively large collecting area of the storage container.
US 2001/0027654 A1 discloses an ice maker assembly disposed within a refrigerator having a freezer and a fresh food compartment. The ice maker assembly comprises a conveyor positioned within the freezer compartment having a flexible conveyor belt with a multiplicity of individual ice cube moulds for creation of individual ice cubes.